Motor assistance for a hybrid vehicle

ABSTRACT

A method of providing assistance to an internal combustion engine for a vehicle using an electric motor coupled to the engine is provided. The method comprises selectively operating the motor to provide assistance to the engine at predetermined operating conditions of the engine. During at least a portion of the selective operation, the motor is operated at a higher torque than a continuous operating torque rating for the motor. The electric motor is coupled to a crankshaft of the engine at a first side of the engine and a transmission is coupled to the crankshaft at a second side of the engine opposite the first side of the engine.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to and the benefit of thefollowing patent applications, the disclosures of which are incorporatedherein by reference in their entireties: Indian Patent Application No.2108/MUM/2009, filed Sep. 15, 2009; Indian Patent Application No.2109/MUM/2009, filed Sep. 15, 2009; International Application No.PCT/IN2009/000655, filed Nov. 15, 2009; International Patent ApplicationNo. PCT/IN2009/000656, filed Nov. 15, 2009; and Indian PatentApplication No. 1390/MUM/2010, filed Apr. 30, 2010.

BACKGROUND

The present disclosure relates generally to the field of vehiclepowertrain systems. More particularly, the present disclosure relates tohybrid vehicle powertrain systems utilizing an engine and a motor.

Most vehicles currently on the road require a relatively large internalcombustion engine to produce power needed for rapid acceleration. Theengine on a standard vehicle is typically sized for the peak powerrequirement. However, most drivers use the peak power of their enginesfor only a small portion (e.g., one percent) of their driving time.Large engines may be heavy and inefficient and may result in higheremissions and/or lower fuel economy.

Vehicle efficiency may be improved through the use of a hybrid systemthat utilizes both an electric motor and an engine. In some hybridsystems, an electric motor may provide power to drive the vehicle over acertain range of operating conditions and an engine may provide power todrive the vehicle over a different range of operating conditions (i.e.,such that only one of the motor and the engine provide power at anygiven time). In other hybrid systems, a motor may assist an engine inproviding power to drive the vehicle. Hybrid systems may be capable ofdelivering required power with a smaller engine than non-hybrid systems.Small engines may be lighter, have fewer cylinders, and/or normallyoperate closer to their maximum load than large engines. The use ofsmall engines may improve the efficiency (e.g., emissions, fuel economy)of a vehicle.

It would be advantageous to provide an improved hybrid system for avehicle that provides improved fuel economy and reduced emissions ascompared to current hybrid systems.

SUMMARY

An exemplary embodiment relates to a method of providing assistance toan internal combustion engine for a vehicle using an electric motorcoupled to the engine. The method comprises selectively operating themotor to provide assistance to the engine at predetermined operatingconditions of the engine. During at least a portion of the selectiveoperation, the motor is operated at a higher torque than a continuousoperating torque rating for the motor. The electric motor is coupled toa crankshaft of the engine at a first side of the engine and atransmission is coupled to the crankshaft at a second side of the engineopposite the first side of the engine.

Another exemplary embodiment relates to a motor controller. The motorcontroller comprises one or more processors configured to executeinstructions stored on one or more computer-readable media. Theinstructions are executable by the one or more processors to selectivelyoperate an electric motor to provide assistance to an internalcombustion engine at predetermined operating conditions of the engine.During at least a portion of the selective operation, the motor isoperated at a higher torque than a continuous operating torque ratingfor the motor. The electric motor is coupled to a crankshaft of theengine at a first side of the engine and a transmission is coupled tothe crankshaft at a second side of the engine opposite the first side ofthe engine.

Another exemplary embodiment relates to a hybrid drive system for avehicle. The hybrid drive system comprises an electric motor configuredto provide assistance to an internal combustion engine to provide motivepower for the vehicle. The hybrid drive system further comprises acontroller configured to control operation of an electric motor. Thecontroller comprises one or more processors configured to executeinstructions stored on one or more computer-readable media, wherein theinstructions are executable by the one or more processors to selectivelyoperate the electric motor to provide assistance to the internalcombustion engine at predetermined operating conditions of the engine.During at least a portion of the selective operation, the motor isoperated at a higher torque than a continuous operating torque ratingfor the motor. The electric motor is coupled to a crankshaft of theengine at a first side of the engine and a transmission is coupled tothe crankshaft at a second side of the engine opposite the first side ofthe engine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic view of a hybrid power system for a vehicleaccording to an exemplary embodiment.

FIG. 1B is a schematic view of a hybrid power system for a vehicleaccording to another exemplary embodiment.

FIG. 2A is a block diagram of a motor control system according to anexemplary embodiment.

FIG. 2B is a more detailed block diagram of a motor control systemaccording to an exemplary embodiment.

FIG. 3A is a flow diagram of a process for controlling a motor toprovide assistance to an engine according to an exemplary embodiment.

FIG. 3B is a flow diagram of a process for determining the assistanceprovided to an engine by a motor according to an exemplary embodiment.

FIG. 3C is a contour graph of the efficiency of a sample engine undervarying operating conditions according to an exemplary embodiment.

FIG. 3D is a graphical representation of emissions data resulting froman emissions test according to an exemplary embodiment.

FIG. 4 is a flow diagram of a process for determining the assistance tobe provided to an engine by a motor according to an exemplaryembodiment.

FIG. 5 is a graphical representation of emissions data resulting from anemissions test with assistance provided by a motor according to anexemplary embodiment.

FIGS. 6A, 6B, 7A, and 7B are graphical representations of emissions dataresulting from emissions tests according to various exemplaryembodiments.

FIGS. 8A through 8D are graphical representations of the efficiency of asample engine under various operating conditions according to exemplaryembodiments.

FIGS. 8E through 8H are histograms related to the data represented inFIGS. 8A through 8D, respectively, according to exemplary embodiments.

DETAILED DESCRIPTION

Referring generally to the figures, systems and methods for assisting anengine in providing driving power for a vehicle are described accordingto various exemplary embodiments. A motor is coupled to the engine andis configured to assist the engine in providing driving power for thevehicle. The motor may be selectively controlled to provide varyinglevels of assistance at different operating conditions. For example,greater assistance may be provided at operating conditions where thebenefit of the assistance (e.g., on reduced emissions, increased fueleconomy, increased power, etc.) is higher, and less assistance may beprovided at operating conditions where the benefit of the assistance islower.

According to various exemplary embodiments, assistance may be providedduring acceleration of the vehicle. The hybrid system may determine(e.g., by receiving signals from one or more sensors) that there is ademand for the vehicle to accelerate (e.g., when the accelerator or gaspedal is depressed). In response, the motor may be controlled to providea pulse of assistance by operating the motor at a current and/or torquehigher than the continuous current and/or torque rating of the motor(e.g., a peak current and/or torque). By operating the motor for a shorttime at a current and/or torque above its continuous rating, the powerdemands of the vehicle may be met and the efficiency (e.g., emissions,fuel economy, etc.) may be improved while using a smaller motor.

There are several advantages to using a smaller motor. For example, asmaller motor may be less expensive than a larger motor and may allowthe hybrid system to be implemented at a lower cost. Because space underthe hood of a vehicle may be limited, use of a smaller motor may allowthe hybrid system to be integrated more easily into vehicles. A smallermotor also may weigh less, resulting in a lower overall vehicle weight,which may in turn provide greater fuel economy and lower emissions. Asmaller motor may also allow electrical power to be provided at a lowervoltage and/or current, which may allow for smaller conductors to beused to provide power between components of the hybrid system and/or mayincrease the safety of the system. According to various embodiments,various other benefits may also be provided by the various featuresdiscussed herein.

Referring now to FIG. 1A, a hybrid drive system 100 and componentsthereof are shown according to an exemplary embodiment. Hybrid drivesystem 100 is configured to be installed within a vehicle (e.g.,automobiles such as cars, trucks, sport utility vehicles, minivans,buses, and the like; tri-pods, scooters, airplanes, boats, etc.), eitherby an original equipment manufacturer and/or by another entity as aretrofit application. Hybrid drive system 100 may selectively reduce thedriving load of an engine and/or increase the torque capacity of anengine by assisting in the rotation of a crankshaft of the engine. Theaddition of hybrid drive system 100 to a vehicle is intended to improvefuel economy, emission rates and/or vehicle power in comparison to thesame vehicle operating without hybrid drive system 100. Hybrid drivesystem 100 may be installed at any suitable location within a vehicleand integrated with any other vehicle components, and may be provided ina wide variety of sizes, shapes, and configurations, and installed usinga wide variety of manufacturing and assembly processes according tovarious exemplary embodiments. All such variations are intended to bewithin the scope of the present disclosure.

FIG. 1A is a schematic illustration of hybrid drive system 100 accordingto an exemplary embodiment. Hybrid drive system 100 generally includesan internal combustion engine 102, an electric motor 104, a motorcontrol unit 106, and a source of electrical power shown in FIG. 1 as abattery pack 108 including a number of energy storage devices in theform of electrochemical cells (although capacitive devices such assupercapacitors and/or ultracapacitors may be used in place of or inaddition to the batteries according to other exemplary embodiments).Internal combustion engine 102 functions as a prime mover of the vehicleby generating a torque output that is sufficient to drive one or morewheels 110 of the vehicle. Electric motor 104 is provided to assistinternal combustion engine 102 by reducing the driving load of internalcombustion engine 102 and/or by augmenting the power of internalcombustion engine 102. Electric motor 104 is powered by battery pack 108and controlled by motor control unit 106.

In addition to assisting internal combustion engine 102 by reducing thedriving load of internal combustion engine 102 and/or by augmenting thepower of internal combustion engine 102, electric motor 104 may also beconfigured to function as a generator for charging battery pack 108and/or for supplying electric energy to various electrical componentswithin the vehicle. Electric motor 104 may be configured to function asa generator (e.g., provide a regeneration function) during one or moreoperating conditions of the vehicle, such as when the vehicle iscoasting down a slope, during braking, when the vehicle is movingforward due to its accumulated momentum (e.g., without the need fordriving power from internal combustion engine 102), and/or during otheroperating conditions. Electric motor 104 may further be configured tosupply mechanical energy (e.g., rotational mechanical energy, etc.) foroperating one or more systems within the vehicle. For example, asdetailed below, electric motor 104 may be used to power a compressorthat is part of an air conditioning system of the vehicle.

Still referring to FIG. 1A, internal combustion engine 102 includes anoutput shaft, shown as a crankshaft 116 having a first output 118 and asecond output 120. First output 118 is configured to be coupled to adrive train of the vehicle for delivering power to one or more of wheels110. According to the embodiment illustrated, the vehicle is a frontwheel drive vehicle and the drive train includes a transmission 122(either an automatic transmission or a manual transmission) coupled tothe front wheels 110 via one or more axles, differentials, linkages,etc. According to the various alternative embodiments, hybrid drivesystem 100 may also be used on a rear-wheel drive vehicle and/or anall-wheel drive vehicle. Internal combustion engine 102 deliversrotational mechanical energy to the drive wheels through transmission122 by rotating crankshaft 116.

Electric motor 104 is coupled in parallel with internal combustionengine 102 to assist internal combustion engine 102 in supplying therotational mechanical energy to transmission 122. According to theembodiment illustrated, electric motor 104 is coupled to second output120 of crankshaft 116; second output 120 being provided at an end ofcrankshaft 116 that is opposite first output 118 such that electricmotor 104 is coupled to an end of crankshaft 116 that is opposite theend which is coupled to transmission 122. Coupling electric motor 104 atsuch a position relative to internal combustion engine 102, rather thanon the same side as transmission 122, may simplify the addition ofhybrid drive system 100, particularly in retro-fit applications.Further, positioning electric motor 104 before transmission 122 allowselectric motor 104 to take advantage of the gearing of transmission 122to reduce the load on electric motor 104. For example, for a vehiclehaving a 5-speed manual transmission, the gear ratios may vary betweenapproximately 3.45 and approximately 0.8 as the gear position is changedfrom first gear to fifth gear. Thus, for the given example, couplingelectric motor 104 to crankshaft 116 before transmission 122 wouldadvantageously allow electric motor 104 to provide an output torque infirst gear that is 3.45 times greater than if the same electric motor104 was coupled to crankshaft 116 after transmission 122. As such, thesystem allows a smaller electric motor 104 to be used to meet the torquedemand of a particular application than if electric motor 104 wascoupled to crankshaft 116 after transmission 116.

Electric motor 104 assists internal combustion engine 102 by assistingin the rotation of crankshaft 116 and thereby reducing the driving loadof internal combustion engine 102 and/or augmenting the power ofinternal combustion engine 102. Because the driving load of internalcombustion engine 102 can be reduced, the fuel consumption and/or theemission rates can be improved. The amount of assistance provided byelectric motor 104, and/or the time period at which assistance isprovided by electric motor 104, may vary depending on the particularneeds and/or parameters of the application in which hybrid drive system100 is being used. The assistance of electric motor 104 may help movethe operation of internal combustion engine 102 into a more efficientoperating zone, resulting in lower emissions, increased fuel economy,etc.

Electric motor 104 generally includes a motor housing 124 and an outputshaft 126. According to an exemplary embodiment, electric motor 104 ispositioned relative to internal combustion engine 102 such that housing124 is adjacent to a side of internal combustion engine 102, with outputshaft 126 being substantially parallel to and offset from crankshaft116. According to the embodiment shown, electric motor 104 is positionedforward of internal combustion engine 102 (relative to a drivingdirection of the vehicle) and is coupled to internal combustion engine102 via a pulley system 126. Pulley system 126 generally includes afirst pulley 128 and a second pulley 130. First pulley 128 is rotatablycoupled to second output 120 of crankshaft 116, while second pulley 130is rotatably coupled to output shaft 124 of electric motor 104. Acoupling device (e.g., chain, strap, etc.), shown as a belt 132, isprovided between first pulley 126 and second pulley 128.

According to the various alternative embodiments, the pulley system maybe replaced with any other suitable coupling system including, but notlimited to, a system of gears. Referring to FIG. 1B, hybrid driversystem 100 is shown according to another exemplary embodiment. Accordingto the embodiment illustrated, electric motor 104 is positioned relativeto internal combustion engine 102 such that an end of housing 124 isfacing an end of internal combustion engine 102 and output shaft 126 isat least partially aligned (e.g., coaxial, concentric, etc.) with secondoutput 120 of crankshaft 116. A shaft coupling (e.g., universal joint,collar, etc.), shown as a universal coupling 136, is provided betweenoutput shaft 126 and second output 120 to directly couple electric motor104 to internal combustion engine 102. Universal coupling 136 isconfigured to compensate for any slight misalignment between outputshaft 126 and second output 120. According to the embodimentillustrated, universal coupling 136 is mounted to first pulley 128,which is rotatably supported by internal combustion engine 102. Similarto the embodiment detailed above with respect to FIG. 1A, first pulley128 may support a belt coupled to at least one of an alternator and acompressor of an air conditioning system.

Referring now to FIG. 2A, a block diagram of a motor control system 200for a hybrid vehicle is shown according to an exemplary embodiment.Motor control system 200 includes a motor controller 204 configured togenerate and/or provide one or more control signals for an electricmotor 205 similar to that described above in conjunction with hybriddrive system 100. Motor controller 204 may include one or moreprocessors (e.g., microcontrollers) and one or more computer-readablemedia (e.g., memory) configured to store various data utilized by motorcontrol system 200 and/or instructions that may be executed by theprocessor(s) to perform various functions. A memory of motor controller204 may include a motor control module that generates the controlsignals for controlling motor 205. In some embodiments, the motorcontrol module may generate the control signals based on one or moremotor assistance profiles such as those discussed in greater detail withrespect to FIGS. 3 and 4. Motor controller 204 may also be configured tomanage energy provided by an energy storage device 203 (e.g., battery,capacitor, array of batteries and/or capacitors, etc.). In variousembodiments, energy storage device 203 may include one or more lead acidbatteries, lithium-ion batteries, nickel-metal-hydride batteries,supercapacitors, and/or other types of energy storage devices.

Motor controller 204 may receive one or more vehicle inputs 201 (e.g.,brake, clutch, vehicle speed, rotational speed, temperature, etc.) fromvarious sensors, circuits and/or other components of the vehicle. Insome embodiments, motor controller 204 may be configured to generatecontrol signals for the motor and/or manage the use of energy fromenergy storage device 203 based on one or more of vehicle inputs 201.Motor controller 204 may be configured to generate one or more systemoutputs 202. In various embodiments, system outputs 202 may include amotor controller power output to toggle power to the motor controller, afault lamp output to indicate a fault, display outputs to displayvarious information about motor controller system 200 (e.g., to a driverof the vehicle, mechanic, etc.), and/or other types of outputs.

Referring now to FIG. 2B, a more detailed block diagram of one possiblemotor control system 240 is shown according to an exemplary embodiment.Motor control system 240 includes a motor controller 254 (e.g., aproportional-integral-derivative, or PID, controller). Motor controller254 includes one or more processors 262 and a memory 264. Memory 264 mayinclude one or more modules (e.g., software modules). The modules storedin memory 264 may include a motor control module 268 configured togenerate one or more control signals to control the operation of a motor260 (e.g., poly-phase motor, single phase motor, AC motor, DC motor,induction motor, etc.). Motor 260 may be coupled to an engine of thevehicle (e.g., by a universal coupling or a belt) and configured toprovide assistance to the engine. In some embodiments, motor controlmodule 268 may generate the control signals based on one or more motorassistance profiles such as those discussed in greater detail withrespect to FIGS. 3 and 4.

The modules may also include an energy management module 266 configuredto manage energy provided by one or more energy storage devices 253.Energy storage devices 253 may include batteries, capacitors, and/orother types of storage devices. In some embodiments, energy storagedevices 253 may be electrically coupled to a capacitor 255 configured totemporarily store charge (e.g., such as energy regenerated by thevehicle during downhill coasting, braking, etc.). Energy storage devices253 may also be connected to a charging device (e.g., for a plug-inhybrid). Energy management module 266 may be configured to determine theamount of available charge remaining in energy storage devices 253. Insome embodiments, energy management module 266, alone or in combinationwith motor control module 268, may be configured to change the controlsignals provided to motor 260 based on the available charge in energystorage devices 253 and/or other vehicle operating conditions.

Motor controller 254 may be configured to receive various inputs fromthe engine, energy storage devices 253, and/or other components of thevehicle. The inputs may include digital inputs 250 (e.g., brake, handbrake, clutch, reverse, air conditioning, ignition, mode selection, suchas economy or power, etc.), modulated and/or encoded inputs 251 (e.g.,vehicle speed sensor, engine speed sensor, encoders, etc.), analoginputs 252 (e.g., motor temperature, engine temperature, temperature forenergy storage device(s), throttle position, manifold pressure, brakeposition, etc.), and/or other types of inputs. In some embodiments,inputs 250, 251, and/or 252 may be isolated through isolator circuitry(e.g., galvanic isolators). Information received at inputs 250, 251,and/or 252 may be received from various vehicle sensors (e.g., existingvehicle sensors, sensors added to vehicle for use by motor controlsystem 240, etc.). In some embodiments, inputs 250, 251, and/or 252 maybe received from a communication link between two or moremicrocontrollers (e.g., engine control or vehicle control modules), suchas by tapping into the link between two controllers. In suchembodiments, links between controllers may be configured to becontroller area network bus (“CAN-bus”) links or links according toanother suitable protocol for communication between two controllers in avehicle.

Motor controller 254 may also be configured to generate one or moreoutputs (e.g., digital outputs, analog outputs, etc.) such as injectoroutputs 256 and/or system outputs 257. Injector outputs 256 areconfigured to control fuel injectors (e.g., through one or morecontrollers) to delay and/or limit the flow of fuel to the engine. Insome embodiments, motor controller 254 may be configured to control thefuel injectors without modifying an engine control unit and/or enginemanagement system. System outputs 257 may include a power supply controloutput, motor controller cooling fan output, fault lamp output, pumpoutput, and/or other types of outputs used to provide information toand/or control various components of the vehicle. Motor controller 254may also be configured to generate display information 258 for displayto a driver of the vehicle (e.g., on a display on or near the dashboardof the vehicle).

Referring now to FIG. 3A, a flow diagram of a process 300 forcontrolling a motor (e.g., motor 104 shown in FIGS. 1A and 1B) toprovide assistance to an engine (e.g., internal combustion engine 102shown in FIGS. 1A and 1B) is shown according to an exemplary embodiment.Process 300 may be used to selectively control and/or operate the motorto provide assistance to the engine at one or more predeterminedoperating conditions of the engine, vehicle and/or hybrid system (e.g.,motor, energy storage device(s), etc.).

At step 302, process 300 monitors one or more operating conditions ofthe engine, vehicle and/or hybrid system. A motor controller may monitoroperating conditions such as linear speed, rotational speed (RPM),engine load, acceleration and/or acceleration demand, etc. The motorcontroller may receive inputs from one or more sensors for use inmonitoring operating conditions of the engine, such as a vehicle speedsensor, an engine speed (e.g., rotational speed) sensor, a throttleposition, a gear position, etc. The motor controller may be configuredto determine (e.g., continuously, periodically, etc.) one or more setsof operating conditions for use in determining the assistance to beprovided by the motor.

At step 304, the assistance to be provided by the motor is selectivelydetermined based on the operating conditions monitored at step 302. Theassistance may be determined according to a motor assistance profilethat defines the level of assistance that should be provided at variousoperating conditions. In one embodiment, the motor assistance profilemay be a lookup table (e.g., stored in a memory associated with themotor controller) having data representing the level of assistance thatshould be provided at different linear speeds and rotational speeds. Fora set of operating conditions observed by the motor controller at step302, the motor controller may be configured to look up the assistancethat should be provided by the motor, if any, in the motor assistanceprofile. The assistance to be provided by the motor may then be setbased on the value contained in the motor assistance profile that mostclosely corresponds with the observed operating conditions. For example,the motor assistance profile may include a value indicating that themotor should provide a low level of assistance (e.g., a motor outputtorque of ten percent of the peak torque) at a speed of 20 km/h and anRPM of 3,200 RPM. In another example, the motor assistance profile mayindicate that the motor should provide a higher level of assistance(e.g., a motor output torque of 90 percent of the peak torque) at aspeed of 50 km/h and an RPM of 1,300 RPM. In various embodiments, theassistance levels reflected in the motor assistance profile may be basedon other operating conditions, such as demand for acceleration, engineload, gear position, etc.

At step 306, signals are generated to control the operation of the motor(e.g., the assistance provided by the motor) based on the assistancelevel determined at step 304. The signals may be generated based on thevalue obtained from the motor assistance profile for the operatingconditions observed at step 302. The generated signals may then be sentto the motor to control the motor's operation and/or the assistanceprovided by the motor to the engine.

In some embodiments, for at least some operating conditions (e.g., whenthe operating conditions indicate a demand for acceleration) the motormay be operated at a higher current (e.g., a peak current) or highertorque (e.g., a peak torque) than the continuous operating rating forthe motor during such operating conditions (e.g., indicating a rapidincrease in emissions and/or power demand or acceleration) for a shorttime or pulse. In some embodiments, the higher current and/or torque atwhich the motor may be operated to provide assistance during suchconditions may be three to four times the continuous rating of themotor. For example, in one embodiment, a motor having a continuouscurrent rating of 50 amps (“A”) may be pulsed at a current level of 180A or at some other (e.g. predetermined) value above the continuous 50 Arating of the motor. In another example, a motor having a continuoustorque rating of 30 Newton-meters (“N-m”) may be pulsed at a torquelevel of 40 N-m or at some other value above the continuous 20 N-mrating of the motor. By operating the motor at a high current and/ortorque in the form of short pulses, a small motor may be utilized (e.g.,providing cost savings, easier integration of the motor with existingcomponents, etc.) without substantially damaging the motor duringoperation at higher current and/or torque levels than the motor'scontinuous rating. Exemplary embodiments in which the motor may beoperated at a current and/or torque that is higher than its ratedcontinuous values are discussed in further detail with reference to FIG.3B.

Referring now to FIG. 3B, a flow diagram of a process 310 fordetermining the assistance to be provided to an engine (e.g., internalcombustion engine 102 shown in FIGS. 1A and 1B) by an electric motor(e.g., motor 104 shown in FIGS. 1A and 1B) is shown according to anexemplary embodiment. Process 310 may be used to determine a motorassistance profile that defines how the motor will assist the engineunder different driving conditions (e.g., the amount of assistance thatwill be provided at different linear and/or rotational speeds). Themotor may be tuned to provide selective assistance to the engine basedon the determined motor assistance profile. In some embodiments, use ofthe motor to assist the engine (e.g., based on the motor assistanceprofile) may allow the engine to operate more efficiently and/or mayprovide for reduced vehicle emissions, reduced fuel consumption (i.e.,increased fuel economy), increased vehicle power, and/or other benefits.

At step 312 of process 310, emissions data is determined (e.g.,collected or received) for an engine of interest across a range ofoperating conditions to characterize the engine. The emissions data mayinclude data relating to carbon monoxide emissions, carbon dioxideemissions, hydrocarbon emissions, nitrogen oxide emissions, and/or othervehicle emissions. In some embodiments, other data (e.g., different thanbut related to emissions data, such as engine load, gear position,acceleration data, etc.) may be used to determine a motor assistanceprofile for the engine. Each type of engine (e.g., petrol, diesel, etc.)is associated with different emissions data (e.g., a different emissionsprofile or curve). For example, the engine of a small hatchback carwould likely result in different emissions data than the engine of alarge truck. Different emissions data or emissions profiles may bedetermined for each type of engine for which the hybrid system isutilized.

In one embodiment, the emissions data may be collected based onemissions testing of the engine of interest. For example, one or moresample engines of a particular type (e.g., an engine used in aparticular car or line of cars) may be tested for emissions. In oneembodiment, emissions may be tested by running the engine on a device(e.g., a dynamometer) configured to measure linear speed and/orrotational speed (e.g., revolutions per minute (“RPM”)) while measuringemission levels (e.g., at the vehicle's tailpipe) using an exhaust gasanalyzer or other emissions measurement device. Linear speed androtational speed are referred to herein as speed and RPM, respectively,but it should be appreciated that other measures of linear and/orrotational speed may be used in various embodiments.

Emissions data may be collected based on the test or tests. In oneembodiment, the emissions data may be configured to reflect arelationship between at least two of linear speed, rotational speed, andengine emissions. In embodiments in which multiple sample engines aretested, the emissions data may be collected and/or calculated based on aselection of the most desirable and/or accurate result or results or acombination of the results (e.g., the average of the results, thestandard deviation of the results, etc.). In one embodiment, a motorassistance profile created based on the emissions data may be used formultiple or all engines of the type tested (e.g., all types or lines ofcars utilizing the tested engine). Determining emissions data for anengine based on test measurements may reduce or eliminate the need forthe individual or entity creating the motor assistance profile to haveaccess to predetermined emissions data for the engine and/or vehicle(e.g., to create the motor assistance profile in a “black box”environment). In other exemplary embodiments, predetermined emissionsdata may be provided for the engine and/or vehicle (e.g., by the engineand/or vehicle manufacturer) and the provided emissions data may be usedto create a motor assistance profile.

Once emissions data has been obtained for the engine of interest, theemissions data is analyzed and a motor assistance profile is createdbased on the analysis of the emissions data (step 314). The motorassistance profile may be designed to direct the motor to assist theengine in a manner that improves the efficiency of the engine andreduces emissions. Referring to FIG. 3C, a contour graph 350 is shownillustrating the efficiency of a particular engine according to anexemplary embodiment. The x-axis of graph 350 represents rotationalspeed in percentage increments between a minimum RPM and a maximum RPM.The y-axis of graph 350 represents the load on the engine (e.g., inmanifold absolute pressure, or MAP) in percentage increments between aminimum load and a maximum load. Graph 350 includes a plurality of zones352 through 370 in which the engine operates under various levels ofefficiency. The engine operates most efficiently when it is run in zone352, which corresponds to a relatively high load and relatively low RPM.Engine load as shown in graph 350 is related to vehicle speed;generally, as the vehicle speed increases, the load on the engineincreases. The efficiency of the engine decreases sequentially as theengine is operated in each zone outside of zone 352. For example, thesecond most efficient zone of operation is zone 354, which isimmediately adjacent to zone 352 in graph 350. The third most efficientzone of operation is zone 356, the fourth most efficient zone is zone358, the fifth most efficient zone is zone 360, and so on. The leastefficient zone (e.g., the zone where the engine emits the greatestemission levels and consumes the most fuel) is zone 372. In someembodiments, process 310 may utilize the motor assistance profile toprovide assistance to the engine and shift the operation away from aless efficient zone to a more efficient zone.

Referring now to FIG. 3D, a graph 375 illustrating emissions data for asample engine or vehicle (e.g., obtained at step 312 of the exemplaryembodiment of FIG. 3B) is shown according to an exemplary embodiment.Graph 375 includes an emissions curve 380 representing the determinedemissions with reference to an emissions axis 382. Emissions axis 382represents emissions in percentage points between a minimum emissionslevel (e.g., in parts per million) and a maximum emissions level. Theemissions reflected in emissions curve 380 in the illustrated exemplaryembodiment are carbon monoxide emissions. In other exemplaryembodiments, the emissions may be carbon dioxide emissions, hydrocarbonemissions, nitrous oxide emissions, or other types of emissions. Graph375 also includes a speed (e.g., linear speed) curve 384 representingthe speed of the vehicle with reference to speed axis 386. Speed axis386 represents linear speed in percentage points between a minimum speed(e.g., in kilometers per hour (“km/h”)) and a maximum speed. Graph 375further includes a time axis 388 representing the time over which thetest is conducted. Time axis 388 represents time in percentage pointsfrom a test start time (e.g., in seconds) to a test end time. In theillustrated exemplary embodiment, the vehicle was progressed through itsgear range from a low to a high speed in increments. For each gear, thevehicle was run at a low speed for the gear and the speed was increased(e.g., in fixed or variable increments) until a high speed for the gearwas reached, at which point the vehicle was shifted into the nexthighest gear. This process was repeated for five gears. Point 390 ontime axis 388 reflects the time at which the vehicle was shifted fromfirst to second gear, point 392 reflects the shift from second to thirdgear, point 394 reflects the shift from third to fourth gear, and point396 reflects the shift from fourth to fifth gear. In various exemplaryembodiments, other tests or variations to the illustrated test may beutilized to obtain emissions data.

Referring again to FIG. 3B, the determination of the engine operatingconditions at which assistance from the motor should be provided and/orthe level or amount of assistance provided is made based upon theemissions data, and a motor assistance profile is created based on thedetermination (step 314). Assistance may be provided over one or moreranges of operating conditions (e.g., ranges of linear and rotationalspeeds) of the engine. The level of assistance may vary between the oneor more ranges and/or within a single range. For example, it may bedetermined that assistance should be provided in a speed range from 20km/h to 90 km/h and/or an RPM range from 1,000 RPM to 3,700 RPM, butthat more assistance should be provided in a lower sub-range of RPM fora particular speed (e.g., for a higher gear) than a higher sub-range ofRPM for that speed (e.g., for a lower gear).

For further example, for the exemplary engine reflected in graph 375 ofFIG. 3D, it may be determined that greater assistance should be providedat point 398, where the RPM is lower, than point 397, where the RPM ishigher. At higher speeds, lower gears operate at a higher RPM thanhigher gears operate at the same speed. For example, immediately priorto point 392, at point 397, the engine operates at a higher RPM insecond gear than it operates immediately after point 392, at point 398,at the same speed in third gear. Providing greater assistance at point398 may have a greater effect on the efficiency of the engine thanproviding greater assistance at point 397; because the RPM is lower atthe same speed at point 398 than at point 397, the emissions are higher(as reflected in emissions curve 380).

Providing assistance to the engine from the motor allows the engine toachieve the desired speed and/or acceleration while operating at a lowerRPM than would be possible if the engine were the sole componentproviding driving power to the vehicle. Referring, for example, to graph350 of FIG. 3C, providing assistance (e.g., at points 397 and/or 398 ingraph 375 of FIG. 3D) may shift the operation of an engine from a lessefficient zone (e.g., zone 368) to a more efficient zone (e.g., zone362).

In some embodiments, some assistance may be provided by the motor overthe full range of engine operating conditions but the extent (e.g.,amount) of the assistance may be varied based on the operatingconditions. Once the appropriate range and/or levels of assistance havebeen determined, a motor assistance profile is generated reflecting thedetermined assistance that should be provided by the motor. The motorassistance profile may be stored in a memory associated with the motorand/or motor controller and may be utilized (e.g., by a motor controlalgorithm) to determine the operating conditions under which the motorshould provide assistance and the level of assistance.

In some embodiments, greater assistance may be provided to the engineduring operating conditions where a rapid increase in power is demanded(e.g., where the emissions data indicates temporarily high emissions orspikes in emissions), such as during acceleration. Inspection of graph375 of FIG. 3D indicates spikes in emissions curve 380 where the vehicleaccelerates (e.g., rapidly) from a lower speed to a higher speed (asreflected in speed curve 384). At these operating conditions, greaterassistance may be provided from the motor to counteract the temporaryincreases in emissions reflected in emissions curve 380 (e.g., such thatthe temporary increases are smaller or have a smaller amplitude thanwithout motor assistance), provide greater power, etc.

In some embodiments, the motor may be operated at a higher current(e.g., a peak current) or higher torque (e.g., a peak torque) than thecontinuous operating rating for the motor during such operatingconditions for a short time or pulse (e.g., as discussed with respect toFIG. 3A). According to various embodiments, the duration and/oramplitude of the pulse may be dependent upon the engine load demand(e.g., acceleration) and/or emissions data. For example, if theemissions data indicates a greater or more prolonged spike in emissions,the pulse applied may be greater in amplitude or size and/or durationthan for a smaller or shorter spike in emissions. In some embodiments, apulse may be applied only if the rate of change of power demandedexceeds a certain level (e.g., if the acceleration exceeds a certainthreshold). In other embodiments, a pulse may be applied whenever thevehicle is called upon to accelerate and/or the amplitude and/orduration of the pulse may be dependent upon the rate of change of powerdemand (e.g., acceleration).

In various embodiments, the motor controller may be configured to limitthe duration and/or amplitude of a pulse to protect against damage tothe motor. In some embodiments, the amplitude of the pulse may belimited so that the current and/or torque provided to the motor does notexceed a recommended peak current and/or torque for the motor (e.g., twoto five times the continuous current rating of the motor). In otherembodiments, the duration of the pulse (e.g., the amount of time thecurrent and/or torque is greater than the continuous rating) may belimited by the temperature of the motor. For example, the motorcontroller may be configured to shorten the duration of a pulse or cutoff a pulse if a motor temperature input indicates that the motor isapproaching a temperature threshold (e.g., a temperature at which themotor may be damaged).

In further embodiments, the determination of the assistance to provideat various engine operating conditions may be based on the frequencywith which a vehicle is expected to be driven within one or more rangesof operating conditions. For example, vehicles may be driven fairlyinfrequently at a low speed such as less than 20 km/h (e.g., becausevery few roads have a speed limit of lower than 20 km/h and drivers tendto accelerate the vehicle fairly quickly to a normal driving speed). Itmay be determined that little or no assistance may be provided at speedswithin this low speed range. In another embodiment, it may be determinedthat little or no assistance is to be provided at operating conditionswhere the speed is within this low range and the RPM is within a highrange (e.g., 2,500 RPM or higher), but greater assistance may beprovided at operating conditions where the speed is within this lowrange and the RPM is within a low range (e.g., 1,000 RPM to 2,500 RPM).

Vehicles may be driven with relatively high frequency in a middle rangeof speeds (e.g., 20 km/h to 80 km/h), such as those speeds at which thevehicle is normally operated in second through fourth or fifth gears(e.g., in the lower range of fifth gear). For example, many roads mayhave posted speed limits within this middle range of speeds. In someembodiments, the motor may be configured to provide greater assistanceto the engine in this middle range of speeds. In further embodiments,the motor may be configured to provide a higher level of assistancewithin this middle range of speeds under those operating conditionswhere the RPM is higher than under conditions where the RPM is lower(e.g., to provide a greater impact on the emissions of the engine and/ormove the engine during those conditions into a more efficient zone ofoperation).

In still further embodiments, the determination of the assistance toprovide may be based at least in part on the battery power available tothe motor and/or a desire to conserve battery power so the charge of thebattery is not depleted too quickly. In some embodiments, thedetermination of the assistance may balance efficiency of the engineand/or reduction of emissions with the time and/or distance a charge isavailable in the battery or batteries. For example, emissions may bevery high for operating conditions where the speed is at a very highrange (e.g., above 90 km/h), but little assistance may be provided atsuch conditions because providing assistance may drain the batteryquickly. In some embodiments, assistance may be gradually removed as thespeed increases within the higher range of speeds.

In some embodiments, the motor assistance may be defined such that themotor provides additional torque to allow the vehicle to be operated ata low RPM as speeds decrease (e.g., allows the vehicle to decrease speedwithout shifting to a lower gear). Under normal operation (e.g., withoutassistance from the motor), the engine may not be able to operate at alow speed (e.g., 10 km/h) while in a higher gear (e.g., fourth gear).Motor assistance may be provided as the vehicle speed is decreased toallow the user to remain in the same gear (e.g., such that the user doesnot need to downshift to avoid stalling the engine). This may allow theengine to operate (e.g., consistently) at a lower RPM at lower speedsrather than proceed through one or more additional gears where theengine may operate at a higher RPM.

Once the motor assistance profile has been created, the motor assistanceprofile may be implemented in the hybrid system (e.g., in connectionwith the motor controller) and emissions data for the engine withassistance from the motor over a range of operating conditions (e.g.,speed and RPM) may be determined (step 315). In some embodiments, thetest (e.g., range of operating parameters, test equipment, etc.) used todetermine the emissions in step 315 may be substantially similar to thetest utilized to determine emissions in 312 for consistency.

The emissions data determined in step 315 may be inspected and/oranalyzed to determine whether further changes to the motor assistanceprofile are desired (step 320). Further changes may be implemented if agreater reduction in emissions than reflected in the emissions datadetermined in step 315 for one or more ranges of operating conditions isdesired. Changes may also be desired if the emissions data determined instep 315 reflects a greater reduction in emissions for one or moreranges of operating conditions than desired and a reduction in motorassistance may be implemented to converse battery power. If furtherchanges to the motor assistance profile are desired, the motorassistance profile may be adjusted to implement the desired changes(step 325) and process 310 may proceed to step 315 and re-determineemissions data for the engine with assistance provided by the motor asdefined in the adjusted motor assistance profile. If further changes tothe motor assistance profile are not desired, the hybrid system (e.g.,motor and/or motor controller) is tuned and/or configured based on themotor assistance profile (step 330).

Various steps of the exemplary embodiment shown in FIG. 3B are describedas being performed based on emissions data. In other exemplaryembodiments, however, similar steps (e.g., analyzing data and creating amotor assistance profile) may be based on other types of data or vehicleinformation. For example, in one embodiment, a motor assistance profilemay be created and/or assistance may be varied based on engine load data(e.g., such that greater assistance may be provided at operatingconditions for which there is a higher load on the engine and lesserassistance may be provided at operating conditions for which there is alower load on the engine). In another embodiment, a motor assistanceprofile may be created and/or assistance may be varied based on a gearposition (e.g., first gear, second gear, third gear, etc., such thatgreater assistance is provided in some gears than in others). In stillfurther embodiments, a motor assistance profile may be created and/orassistance may be varied based on acceleration data and/or anaccelerator (e.g., gas pedal) position.

Referring now to FIG. 4, a flow diagram of a process 400 for determiningthe assistance to be provided to an engine (e.g., engine 102 shown inFIGS. 1A and 1B) by a motor (e.g., motor 104 shown in FIGS. 1A and 1B)is shown according to an exemplary embodiment. Various steps of process400 may be performed using methods, components, structure, etc.discussed with respect to steps of the exemplary process 310 of FIG. 3B.Process 400 begins by determining emissions data for the engine. Varioussteps of process 400 may be utilized, for example, to measure emissionsdata for an engine if emissions data is not previously known or providedby a manufacturer (e.g., in a “black box” environment). At step 405, ifthe engine and/or vehicle is currently in a hybrid mode, the hybrid modeis turned off. The engine emissions data is then measured over a rangeof operating conditions (e.g., linear speeds, rotational speeds, etc.)(step 410). In one embodiment, operating conditions may be monitoredusing a dynamometer and emissions data may be measured using anemissions gas analyzer (e.g., for analyzing tailpipe emissions).

In some embodiments, an emissions chart or graph (such as graph 375 ofFIG. 3D) may be generated based on the measured emissions data (step415). According to various embodiments, analysis of engine emissionsdata and/or creation of one or more motor assistance profiles may beperformed either manually (e.g., by one or more humans inspecting theemissions data) or by software (e.g., through computerized analysis ofemissions data to determine appropriate ranges of operating conditionsand/or levels of assistance). In one example, an emissions chart may becreated at step 415 if a motor assistance profile is being createdmanually to assist the individual(s) creating the motor assistanceprofile in visually analyzing the emissions data.

At step 420, it is determined whether reference hybrid emissions data isdesired. In some embodiments, reference hybrid emissions data may begenerated as a reference for how much benefit would be provided if thevehicle were operated in hybrid mode and the motor assistance was notprovided based on a motor assistance profile (e.g., if a fixed level ofmotor assistance were provided across the full range of operatingconditions). If reference hybrid emissions data is not desired, process400 proceeds to step 425 to analyze the engine emissions data and createa motor control profile. If reference hybrid emissions data is desired,process 400 determines whether reference hybrid emissions data hasalready been measured (step 430). If so, process 400 proceeds to step425. If reference hybrid emissions data has not already been measured,hybrid mode is turned on (step 435) and steps 410 and, optionally, 415are repeated in hybrid mode.

At step 425, the emissions data is analyzed and a motor assistanceprofile is created. Once the motor assistance profile has been created,new emissions data reflecting operation of the engine with assistancefrom the motor (based on the motor assistance profile) is determined(e.g., measured or calculated). In some embodiments, the new emissionsdata may be graphically represented in a chart or graph (step 445). Atstep 450, the new emissions data is compared with the emissions datameasured at step 410 to determine if the motor assistance profileresults in desired emissions levels for the hybrid system. In someembodiments, the new emissions data may also be compared with thereference hybrid emissions data. At step 455, process 400 determines iffurther changes to the motor assistance profile (and, accordingly, theresultant emissions data) are desired. If further changes are desired,adjustments are made to the motor assistance profile (step 460) andsteps 440, 445 (optionally), 450, and 455 are repeated. Multiple changesmay be made to the motor assistance profile and these steps may berepeated multiple times to refine the motor assistance profile andachieve the desired emissions. Once the desired motor assistance profilehas been created and no more changes are preferred, the motor assistanceprofile may be stored (e.g., in a memory of a motor controller) and maybe used to control the assistance provided by the motor (e.g., usingcontrol signals generated by a motor controller and based on the motorassistance profile) (step 465).

Referring now to FIG. 5, a graph 500 of emissions data resulting from anemissions test with assistance provided by a motor is shown according toan exemplary embodiment. The data shown in graph 500 may be obtainedusing a similar or same test as graph 375 of FIG. 3D (e.g., showing datafor a vehicle without assistance from a motor). Graph 500 includes anemissions curve 505 representing emissions data that may be obtained fora vehicle including a hybrid system that provides selective assistancefrom a motor according to various exemplary embodiments describedherein.

The effect of the difference between operating without assistance from amotor and operating with assistance is evident upon comparison ofemissions curve 380 of graph 375 and emissions curve 505 of graph 500.Comparison of the two emissions curves clearly shows that the totalemissions over the range of the emissions test are substantially lowerin emissions curve 505, with selective assistance from a motor, than inemissions curve 380, with no motor assistance. Further, comparison ofthe two emissions curves shows that different levels of assistance areprovided at different operating conditions. For example, greaterassistance appears to be provided in a speed range from 25 percent to 67percent, where the difference between emissions curves 380 and 505 ispronounced, than in a speed range of zero percent to 25 percent, wherethe difference between emissions curves 380 and 505 is less pronounced.

A vehicle that utilizes selective assistance from a motor, as describedherein according to various exemplary embodiments, may achievesubstantial reductions in emissions and/or increases in fuel economy. Inone example, for a driving range of approximately 11 km, a vehicleutilizing a hybrid system that provides assistance to the engine mayresult in a reduction in carbon monoxide emissions of about 43 percent,a reduction in hydrocarbon emissions of about 16 percent, a reduction innitrous oxide emissions of about 53 percent, a reduction in carbondioxide emissions of about 35 percent, and/or an increase in fueleconomy of about 55 percent as compared to a similar vehicle withoutmotor assistance. In various other exemplary embodiments, benefits maybe even more substantial depending on the assistance provided to theengine, the stored energy available to the system, the expected drivingrange, and/or other factors. In some embodiments, fuel economy mayincrease up to 130 percent or greater by utilizing assistance from amotor.

Referring now to FIGS. 6A, 6B, 7A, and 7B, graphical representations ofemissions data resulting from another emissions test is shown accordingto various exemplary embodiments. The underlying emissions test in FIGS.6A through 7B is different than the test underlying FIGS. 3D and 5. Theunderlying emissions test shown in FIGS. 6A through 7B is a driving testin which the vehicle is quickly accelerated from a stop to severaldifferent speeds and then returned to a stop after each speed isattained (as shown by speed curve 605). The vehicle is then acceleratedto a higher speed (e.g., 70 percent of a highest speed in a speedrange), slowed to a lower speed (e.g., 50 percent), returned to thehigher speed (e.g., 70 percent), and then accelerated to an even higherspeed (e.g., 90 percent) before the vehicle is brought to a stop.

FIG. 6A includes a graph 600 that illustrates carbon dioxide emissionsdata that may result from running the test on a vehicle without motorassistance (e.g., a non-hybrid vehicle). Carbon dioxide emissions curve610 is a graphical illustration of the carbon dioxide emissions datathat may be obtained under such a test. FIG. 6B includes a graph 620that illustrates carbon dioxide emissions data that may result fromrunning the test on a similar vehicle with motor assistance (e.g., in ahybrid mode). Carbon dioxide emissions curve 630 is a graphicalillustration of the carbon dioxide emissions data that may be obtainedunder the test in a hybrid mode utilizing features as discussed herein.Comparison of emissions curves 610 and 630 demonstrates that carbondioxide emissions may be selectively reduced at several differentoperating conditions by utilizing assistance from a motor.

FIG. 7A includes a graph 700 that illustrates carbon monoxide emissionsdata that may result from running the test on a non-hybrid vehicle.Carbon monoxide emissions curve 710 is a graphical illustration of thecarbon monoxide emissions data that may be obtained under such a test.FIG. 7B includes a graph 720 that illustrates carbon monoxide emissionsdata that may result from running the test on a similar vehicle withmotor assistance (e.g., in a hybrid mode). Carbon monoxide emissionscurve 730 is a graphical illustration of the carbon monoxide emissionsdata that may be obtained under the test in a hybrid mode utilizingfeatures as discussed herein. Comparison of emissions curves 710 and 730demonstrates that carbon monoxide emissions may also be selectivelyreduced at several different operating conditions by utilizingassistance from a motor.

Referring now to FIGS. 8A through 8D, four graphs 800, 805, 810, and 815are provided illustrating sample results that may be attained byutilizing various exemplary embodiments of a hybrid system as discussedherein with respect to FIGS. 1 through 4. The x-axes of graphs 500 800,805, 810, and 815 represent rotational speed in percentage incrementsbetween a minimum RPM and a maximum RPM. The y-axes of graphs 800, 805,810, and 815 represent the load on the engine (e.g., measured inmanifold absolute pressure, or MAP) in percentage increments between aminimum load and a maximum load. Each of the dots displayed on graphs800, 805, 810, and 815 represent data points collected at differentpoints in time and/or different operating conditions during a drivingsimulation test.

Referring now specifically to FIGS. 8A and 8B, two graphs 800 and 805illustrate exemplary data for a non-hybrid vehicle or a vehicle in whicha hybrid mode is not activated. Graph 800 illustrates data for anon-hybrid vehicle being operated with the air conditioning systemturned on, and graph 805 illustrates data for a non-hybrid vehicle beingoperated with the air conditioning system turned off. Graphs 800 and 805reflect data for an engine that is receiving no assistance from a motor.The data points shown in graphs 800 and 805 are concentrated largely atrelatively high rotational speeds, indicating that the engine isfrequently operating at a high RPM.

Referring now to FIGS. 8C and 8D, graphs 810 and 815 illustrateexemplary data for a vehicle (e.g., the same or a similar vehicle) inwhich a hybrid system such as that described with respect to FIGS. 1through 4 is active and assistance is being provided to the engine by amotor. Graph 810 illustrates data for a hybrid vehicle being operatedwith the air conditioning turned on, and graph 815 illustrates data fora hybrid vehicle with optimum gear shifting (e.g., where the vehicle wasshifted between gears at the most efficient times and/or operatingconditions). The data points in graphs 810 and 815 are generallyconcentrated at lower rotational speeds than in graphs 800 and 805,indicating that the engine is more frequently operating in a lower RPMrange than when the hybrid system is not activated (e.g., as shown ingraphs 800 and 805).

The effect of the difference between operating without assistance from amotor and operating with assistance is evident upon comparison of FIGS.8A through 8D with FIG. 3B. Referring to FIG. 3B, an engine is morefrequently operating in a more efficient zone of operation when it isrunning at a lower RPM. Comparing each of FIGS. 8A through 8D with FIG.3B (e.g., FIGS. 8A and 8C), it can be seen that a larger amount of datapoints are within more efficient zones of operation in FIGS. 8C and 8D(e.g., reflecting assistance provided by the motor) than in FIGS. 8A and8B (e.g., reflecting no provided assistance).

The effect of the assistance is further evident upon comparison of thedata in FIGS. 8E through 8H. FIGS. 8E through 8H illustrate histogramsrelated to the data represented in FIGS. 8A through 8D, respectively,according to exemplary embodiments. FIGS. 8E through 8H includehistograms 820, 825, 830, and 835, generated based on the distributionof data points shown in graphs 800, 805, 810, and 815, respectively.Histograms 820, 825, 830, and 835 provide another method for analyzingthe frequency with which the engine is operating at different RPM rangesin the exemplary embodiments shown in FIGS. 8A through 8D. Comparison ofhistograms 820 and 825 with histograms 830 and 835 demonstrates that theengine may more frequently operate at a lower RPM when receivingassistance from a motor than when no assistance is received. Asdiscussed with respect to FIG. 3C, an engine may operate in a moreefficient zone of operation when it runs at a lower RPM.

As utilized herein, the terms “approximately,” “about,” “substantially,”and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and areconsidered to be within the scope of the disclosure.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

It should be noted that the orientation of various elements may differaccording to other exemplary embodiments, and that such variations areintended to be encompassed by the present disclosure.

It is important to note that the construction and arrangement ofelements shown in the various exemplary embodiments is illustrativeonly. Other substitutions, modifications, changes and omissions may alsobe made in the design and arrangement of the various exemplaryembodiments without departing from the scope of the present disclosure.

The present disclosure contemplates methods, systems and programproducts on any machine-readable media for accomplishing variousoperations. The embodiments of the present disclosure may be implementedusing existing integrated circuits, computer processors, or by a specialpurpose computer processor for an appropriate system, incorporated forthis or another purpose, or by a hardwired system. Embodiments withinthe scope of the present disclosure include program products comprisingmachine-readable media for carrying or having machine-executableinstructions or data structures stored thereon. Such machine-readablemedia can be any available media that can be accessed by a generalpurpose or special purpose computer or other machine with a processor.By way of example, such machine-readable media can comprise RAM, ROM,EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic diskstorage or other magnetic storage devices, or any other medium which canbe used to carry or store desired program code in the form ofmachine-executable instructions or data structures and which can beaccessed by a general purpose or special purpose computer or othermachine with a processor. When information is transferred or providedover a network or another communications connection (either hardwired,wireless, or a combination of hardwired or wireless) to a machine, themachine properly views the connection as a machine-readable medium.Thus, any such connection is properly termed a machine-readable medium.Combinations of the above are also included within the scope ofmachine-readable media. Machine-executable instructions include, forexample, instructions and data which cause a general purpose computer,special purpose computer, or special purpose processing machines toperform a certain function or group of functions.

Although the figures may show a specific order of method steps, theorder of the steps may differ from what is depicted. Also two or moresteps may be performed concurrently or with partial concurrence. Invarious embodiments, more, less or different steps may be utilized withrespect to a particular method without departing from the scope of thepresent disclosure. Such variation will depend on the software andhardware systems chosen and on designer choice. All such variations arewithin the scope of the disclosure. Likewise, software implementationscould be accomplished with standard programming techniques with rulebased logic and other logic to accomplish the various connection steps,processing steps, comparison steps and decision steps.

What is claimed is:
 1. A method of providing assistance to an internalcombustion engine for a vehicle using an electric motor coupled to theengine, the method comprising: selectively operating the motor toprovide assistance to the engine at predetermined operating conditionsof the engine; wherein the electric motor is coupled to a crankshaft ofthe engine at a first side of the engine and a transmission is coupledto the crankshaft at a second side of the engine opposite the first sideof the engine; and wherein during at least a portion of the selectiveoperation, the motor is operated at a higher torque than a continuousoperating torque rating for the motor, wherein operating the motor at ahigher torque than a continuous operating torque rating for the motorallows the motor to provide a same level of assistance to the engine asif a larger motor were used to provide assistance to the engine.
 2. Themethod of claim 1, wherein the motor is operated at a peak torque forthe motor during the time when the motor is operated at a higher torquethan a continuous operating torque for the motor.
 3. The method of claim2, wherein the peak torque is at least three times the continuous torquerating of the motor.
 4. The method of claim 1, further comprisinglimiting the duration during which the motor is operated above itscontinuous operating torque rating based on a temperature of the motor.5. The method of claim 1, wherein the step of selectively operating themotor comprises: determining acceleration data for the vehicle based oninput received from one or more sensors; and generating one or morecontrol signals configured to control operation of the electric motorwhen the acceleration data indicates a demand for acceleration.
 6. Themethod of claim 5, wherein selectively operating the motor comprisesoperating the motor for a first duration when the acceleration dataindicates a higher acceleration demand and for a second duration whenthe acceleration data indicates a lower acceleration demand, the firstduration being longer than the second duration.
 7. The method of claim5, wherein the one or more control signals are configured to control theelectric motor to provide greater assistance in a first RPM range thanin a second RPM range, wherein the first RPM range is lower than thesecond RPM range.
 8. The method of claim 5, wherein the one or morecontrol signals are configured to control the electric motor to providegreater assistance in one or more middle gears than in at least one of alowest gear and a highest gear.
 9. The method of claim 5, wherein theone or more control signals are based on a motor assistance profile thatis based on emissions data for the internal combustion engine.
 10. Themethod of claim 9, wherein the one or more control signals areconfigured to control the electric motor to provide greater assistanceduring a first operating condition than during a second operatingcondition, wherein the emissions data indicates higher emissions duringthe first operating condition than the second operating condition.
 11. Amotor controller, comprising: one or more processors configured toexecute instructions stored on one or more computer-readable media,wherein the instructions are executable by the one or more processors toselectively operate an electric motor to provide assistance to aninternal combustion engine at predetermined operating conditions of theengine; wherein the electric motor is coupled to a crankshaft of theengine at a first side of the engine and a transmission is coupled tothe crankshaft at a second side of the engine opposite the first side ofthe engine; and wherein during at least a portion of the selectiveoperation, the motor is operated at a higher torque than a continuousoperating torque rating for the motor, wherein operating the motor at ahigher torque than a continuous operating torque rating for the motorallows the motor to provide a same level of assistance to the engine asif a larger motor were used to provide assistance to the engine.
 12. Themotor controller of claim 11, wherein the motor is operated at a peaktorque for the motor during the time when the motor is operated at ahigher torque than a continuous operating torque for the motor.
 13. Themotor controller of claim 12, wherein the peak torque is at least threetimes the continuous torque rating of the motor.
 14. The motorcontroller of claim 11, wherein the duration during which the motor isoperated above its continuous operating torque rating is limited basedon a temperature of the motor.
 15. The motor controller of claim 11,wherein selectively operating the motor comprises: determiningacceleration data for the vehicle based on input received from one ormore sensors; and generating one or more control signals configured tocontrol operation of the electric motor when the acceleration dataindicates a demand for acceleration.
 16. The motor controller of claim15, wherein selectively operating the motor comprises operating themotor for a first duration when the acceleration data indicates a higheracceleration demand and for a second duration when the acceleration dataindicates a lower acceleration demand, the first duration being longerthan the second duration.
 17. The motor controller of claim 15, whereinthe one or more control signals are configured to control the electricmotor to provide greater assistance in a first RPM range than in asecond RPM range, wherein the first RPM range is lower than the secondRPM range.
 18. The motor controller of claim 15, wherein the one or morecontrol signals are configured to control the electric motor to providegreater assistance in one or more middle gears than in at least one of alowest gear and a highest gear.
 19. The motor controller of claim 15,wherein the one or more control signals are based on a motor assistanceprofile that is based on emissions data for the internal combustionengine.
 20. The motor controller of claim 19, wherein the one or morecontrol signals are configured to control the electric motor to providegreater assistance during a first operating condition than during asecond operating condition, wherein the emissions data indicates higheremissions during the first operating condition than the second operatingcondition.
 21. A hybrid drive system for a vehicle, comprising: anelectric motor configured to provide assistance to an internalcombustion engine to provide motive power for the vehicle; and acontroller configured to control operation of an electric motor, whereinthe controller comprises one or more processors configured to executeinstructions stored on one or more computer-readable media, wherein theinstructions are executable by the one or more processors to selectivelyoperate the electric motor to provide assistance to the internalcombustion engine at predetermined operating conditions of the engine;wherein the electric motor is coupled to a crankshaft of the engine at afirst side of the engine and a transmission is coupled to the crankshaftat a second side of the engine opposite the first side of the engine;and wherein during at least a portion of the selective operation, themotor is operated at a higher torque than a continuous operating torquerating for the motor, wherein operating the motor at a higher torquethan a continuous operating torque rating for the motor allows the motorto provide a same level of assistance to the engine as if a larger motorwere used to provide assistance to the engine.
 22. The hybrid drivesystem of claim 21, wherein the motor is operated at a peak torque forthe motor during the time when the motor is operated at a higher torquethan a continuous operating torque for the motor.
 23. The hybrid drivesystem of claim 22, wherein the peak torque is at least three times thecontinuous torque rating of the motor.
 24. The hybrid drive system ofclaim 21, wherein the duration during which the motor is operated aboveits continuous operating torque rating is limited based on a temperatureof the motor.
 25. The hybrid drive system of claim 21, whereinselectively operating the motor comprises: determining acceleration datafor the vehicle based on input received from one or more sensors; andgenerating one or more control signals configured to control operationof the electric motor when the acceleration data indicates a demand foracceleration.
 26. The hybrid drive system of claim 25, whereinselectively operating the motor comprises operating the motor for afirst duration when the acceleration data indicates a higheracceleration demand and for a second duration when the acceleration dataindicates a lower acceleration demand, the first duration being longerthan the second duration.
 27. The hybrid drive system of claim 25,wherein the one or more control signals are configured to control theelectric motor to provide greater assistance in a first RPM range thanin a second RPM range, wherein the first RPM range is lower than thesecond RPM range.
 28. The hybrid drive system of claim 25, wherein theone or more control signals are configured to control the electric motorto provide greater assistance in one or more middle gears than in atleast one of a lowest gear and a highest gear.
 29. The hybrid drivesystem of claim 25, wherein the one or more control signals are based ona motor assistance profile that is based on emissions data for theinternal combustion engine.
 30. The hybrid drive system of claim 29,wherein the one or more control signals are configured to control theelectric motor to provide greater assistance during a first operatingcondition than during a second operating condition, wherein theemissions data indicates higher emissions during the first operatingcondition than the second operating condition.